Harpsund is well-known for being the residence for the Swedish prime minister. Besides this function, it is also a big production unit for milk and meat, with a livestock herd of about 500 animals. At Harpsund, a new production plant for heating and domestic hot water with a new distribution network was built by the Swedish authorities Statens Fastighetsver” and Harpsundsnämnde”. Wood chips from the forests belonging to the estate are used for heat production together with wood pellets and solar heat. The old heating system was based on a technique with local production in each building and was in need of modernization. The new plant was designed very attractively; great care was taken to make it fit into the surroundings. The solar collectors are placed on the roof of a garage for farming machines and they are easily seen from the road leading into the building complex.